Question

Which of the following relations is a function?
A:{(0,2) (1,2) (2,2) (3,2)}
B:{(2,0) (2,1) (2,2) (2,3)}
C:{(3,5) (4,7) (5,9) (5,11)}
D:{(4,5) (6,7) (8,9) (8,11)}

Answer 1

A function is a set of ordered pairs (x,y) such that for each x there is a unique y value for that x.

The same x cannot be paired to two different y-values.

Answer 2

@boatsandhoes

Let's take a look at this answer option: B:{(2,0) (2,1) (2,2) (2,3)}
Notice that the x of 2 is paired with four different y values.
So, the set of points in the relation for option B do not make a function.
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Look at your other answer options and throw out any that have the same x going to two or more different y-values for that x.

Post what you get and somebody will check it for you, if you like.